Vessel propelled by gas discharged below the water level



Nov. 27 1923. H 1,475,393"

H. A. J. DE B. NACHENIUS VESSEL PROPELLED BY GAS DISCHARGED BELOW THEWATER LEVEL Filed July 5. 1922 2 Sheets-Sheet 1 W ,4 #4 Mg- Nov.- 27T923. 7 1,475,393

7 H. A. J. DE 18. NACHENIUS V VESSEL PROPELLED BY GAS DISCHARGED BELOWTHE WATER LEVEL Filed July 3, 1-922 Shoots-Sheet 2 by ya Q/w PatentedNov. 27, 1923.

HENRI ARNOLD JoHAnnns DE ennnnaonnmus, or I-IAABLEM, NETHERLANDS.

1,475,393 PATENT jiOFFICFEF).

.VESSEL PROBELILED areas DISCHARGED BELOW THE WATER LEVEL I Applicationfiled July 3,

To all whom it may concern:

Be it known that I, HENRI AnNoLo JOHANNES on BIJLL NACHENIUS, a subjectof the Queen of the Netherlands, residing at Haarlem, Netherlands, haveinvented certain new and useful Improvements in Vessels Propelled by GasDischarged Below the Water Level, of which the following is aspecification.

This invention relates to an improvement in 01' modification of vesselsadapted to be propelled by gas (usually air) discharged below the waterlevel with a pressure which does not appreciably exceed the waterpressure at the outlet, and having a substantially plane, upwardlyinclined stern face for guiding the rising gas bubbles.

In the drawings,

Figure 1 is a side view of the stern without the horizontal extension.

Figure 2 is a side view of the device in operation.

Figure 3 is a side view of a slight modification.

Figure 4 is a side view of the vessel showing the position of the gasoutlet.

The gas bubbles rising to the water level along the inclined planeforming the stern face 1 (see Figure 1) which extends through the entireor the greater part of the width of the vessel produce a water currentin substantially parallel relation with the stern face. Said currenthas, of course, a tendency to continue its movement in the samedirection above the water level but this is prevented by the action ofgravity, that is to say, a Wave is formed at the stern of the vessel asindicated by a (Figure 1). This wave formation means a loss of energy asthe energy required for lifting the water above the water level cannotbe used for propelling'the vessel.

The gas outlet is positioned along the bottom of the vessel, as shown at3, of Figure 4. Of course several outlets might be used if desired, oneonly being shown in the drawing.

The object of the present invention is t reduce this loss of energy. Inaccordance with the invention the wave formation at the stern of thevessel may be avoided or reduced by securing to the vessel, approxi-.

mately flush with the water level, a horizontal plate 2 (Fig. 2) whichextends through substantially the full width of the 19 22. seams.572,583.

vessel so as to constitute the end portion or the extension of theinclined face 1. This plate has for its duty to impart just at the waterlevel a horizontal movement to the water current rising along the face 1in a direction opposite to that of the vessel, .Whereby the fullreaction of the water current is available for propelling the vessel.Practical tests have already shown that by these means it is indeedpossible to increase the speed of the vessel. 7

Assuming the velocity of the water current along the inclined stern faceto be 4) and the angle between said face and a horizontal plane to be a,the component producing the wave formation is 1: sin a. This componentis almost entirely transformed by the horizontal plate 2 into anincrease of pressure of the uppermost water strata.

aid increase of pressure, corresponding with a head of water of i) sin a9 increases the speed of the vessel and also the velocity of the Watercurrent in the opposite direction.

It is obvious that the effect of the horizontal plate 2 is maximum whensaid plate is arranged exactly at the water level. W'ith a view to thevarying draught of the vessel said plate should, therefore, bevertically adjustable, that is to say, it should be secured at therequired level to the vessel every time the latter begins a voyage.This, however, meets in many cases with serious difliculties. With aview to this fact the stern face of the vessel may be made concave(viewed from the side), either broken or curved, in such a manner thatthe tangent to this surface forms with the horizontal plane an anglewhich at the maximum draught is 0 at the waterlevel and which graduallyincreases downwardly (see Figure 3 of the drawing). If, now, the draughtof thevessel is maximum, the Wave formation is completely prevented bythe horizontal portion of the stern face, whereas at a decreaseddraught, within a certain limit, still a useful effect is obtained overthe construction shown in Figure 2.

. What I claim is:

1. In a vessel adapted to be propelled by gas dischar ed below the boatbottom with no apprecia le over-pressure, an upwardly 5 having anapproximately horizontalcxt-envessels.v

sloping stern face for guiding rising gas upwardly sloping stern facebeing concave. 10 bubbles from the boat bottom to'the 'surface {.3. Infavessel according to claim l, the of the water, said stern face extending"subsaid approximately horizontal surface bestantially the entire widthof the vessel, and ing vertically adjustable with respect to the sionsurface substantially flush with the In testimony whereof I aflix mysignature. water level. i y 'HENRYARNOLDlJOHANNES 2. In a vesselaccording to claim 1, said de BULL NACHENlUS-

